Hi all. I've been using Isilo 4.15 for a couple of weeks and have been very pleased with how it works and how pages turn out on my zire 71. I just purchased a 256mb SD card (Kingmax 60x) because it was supposed to be faster (read and write speeds) than my 128mb Lexar. However, when I sync, the Isilo part of it grinds to a halt and takes twice as long to sync the same pages I was syncing before. It takes up to 10-15 minutes to complete, where it was only taking about five before. I also bought a Kingston 256mb SD card that does the same way, but I thought it was the speed of the card causing the sloooow down, but now I am wondering....please help.